1. Technical Field
The present invention relates to a radio base station and a mobile communication method.
2. Background Art
A mobile communication system of the LTE (Long Term Evolution) scheme is configured such that a mobile station UE transmits an RA (Random Access) preamble via a PRACH (Physical Random Access Channel) in order to start a random access procedure performed at a start of communication.
However, the above-mentioned mobile communication system has a problem that when a plurality of mobile stations UE visit a same cell, for example, RA preambles simultaneously transmitted by the plurality of mobile stations UE collide, and thus, a success probability of a random access procedure is lowered.